Twisted yarns are in general produced in a multi-step method whereby the known methods and devices substantially comprise the following individual steps, respectively, individual features:
1. From a roving supply rovings are guided via a drawing device to a ring spinning spindle on which the spun yarns are wound onto spool sleeves. The resulting bobbins, mostly in the form of cops, are rewound in a second method step on a winding machine to form cross-wound spools. In a third method step two or more cross-wound spools are rewound on a doubling winder. The doubled cross-wound spools are then used as a supply in a fourth method step, for example, in a two-for-one twisting machine in order to manufacture the finished twisted yarn. PA1 2. Spun yarns are produced according to the open end spinning process and are wound onto sleeves to form cross-wound spools. As needed, two or more of these cross-wound spools are subsequently wound on a doubling winder to a doubled cross-wound spool. The cross-wounds spools are then used in pairs or, in the case of a doubled cross-wound spool, as a single spool for twisting on a two-for-one twisting spindle. PA1 3. In order to unify the three processes spinning, winding, and twisting into a single continuous process a yarn cop that has been produced, for example, on a conventional ring spinning spindle is placed on a hollow spindle. A roving being supplied from a separate roving supply, for example, in the form of a beam creel, passes through a conventional drawing device and is then introduced together with the spun yarn of the yarn cops positioned on the hollow spindle into the hollow spindle axle. The yarn of the yarn spool is withdrawn due to the spindle rotation and runs together with the pre-drawn roving through the hollow spindle to a winding device, respectively, a winding location. This is, for example, disclosed in "Eine neue Spinnzwirnmaschine" "Melliand-Textilberichte 12/1966", pages 1354 and 1355. PA1 4. According to German Offenlegungschrift 31 48 874 machines with drawing devices and rewinding spindles are known whereby the yarns, supplied via the drawing device, are guided through the axles of the hollow spindle, optionally with twisting, to a winding device via supply cylinders. The hollow spindles must be supplied with cops or parallel wound spools of special embodiments. The yarns of these cops or spools cannot be compared to the spool bodies according to paragraphs 1 and 2 supra. They have only the type of winding of a cop winding or a parallel wound disk spool and are not produced on spinning machines but instead on respective winding machines. The yarn supply of the spool body is in most cases a filament yarn. By rotating the hollow spindle in a predetermined rotational direction and by preadjusted the rpm ratios (rpm=revolutions per minute) of drawing device, supply cylinder, and winding action a wrapped yarn is produced. PA1 5. In German Offenlegungschrift 42 35 433 a method for manufacturing a twisted yarn is disclosed in which in a first method step a roving, removed from a roving supply and guided through a drawing device, is spun by a ring spinning process and is wound onto a yarn carrier permanently attached to a hollow spindle in order to produce a spun yarn body. In a second step the spinning process is interrupted and the spun yarn, which has been previously wound to form the spun yarn body, is removed from the spun yarn body under balloon formation. Together with a roving, removed from a roving supply and stretched in a drawing device, the spun yarn is guided through the hollow axle of a hollow spindle to a winding device whereby the hollow spindle as a function of the feed velocity of the friction rollers of the winding device is being rotated such that the twist of the spun yarn is canceled. PA1 Removing two rovings from two separate supplies; PA1 Passing each roving through a separate drawing device; PA1 Ring-spinning from each roving a separate spun yarn; PA1 Collecting each spun yarn as a bobbin on a yarn carrier of separate hollow spindles, wherein the separate hollow spindles are positioned atop one another; PA1 Withdrawing with formation of a yarn balloon from the bobbins the spun yarns and guiding each spun yarn through the hollow spindle axle of the respective hollow spindle; PA1 Routing the spun yarn withdrawn from the upper one of the hollow spindles through the hollow spindle axle of the lower one of the hollow spindles; PA1 Guiding both spun yarns together to a winding device positioned below the lower one of the hollow spindles; PA1 Rotating the hollow spindles as a function of the winding speed of the winding device such that a twist of the spun fibers is at least partially canceled. PA1 A first and a second spindle support frame arranged one atop the other; PA1 At least one pair of ring spinning devices, with one of the ring spinning devices connected to the first spindle support frame and the other ring spinning device connected to the second spindle support frame; PA1 Each one of the ring spinning devices comprising a hollow spindle with a permanently installed yarn carrier; and PA1 At least one winding device position below the hollow spindles.
By eliminating the third method step it is also possible to supply the two-for-one twisting machine directly with two cross-wound spools produced by the winding machine for manufacturing the finished twisted yarn.
Even though the process described in paragraph 3 supra claims to combine the three processes spinning, twisting, and winding into a single continuous process, it is obvious that this method for the reasons disclosed above cannot completely fulfill this claim because it is always necessary in a first method step, for example, with a conventional ring spinning machine, to produce a spun yarn which is wound on the ring spinning machine to a cop that is then, according to the method described in paragraph 3 supra, twisted together with the predrawn roving. The yarn body produced on a ring spinning machine thus has to be transported between machines of almost identical function and processing steps whereby especially the removal and reinsertion of yarn spools, on the one hand, and of empty spools, on the other hand, requires a considerable manipulation expenditure which especially with automated method steps results in a high investments for the automation of the machine.
A substantially identical method is also disclosed in U.S. Pat. No. 3,425,209. In this method the twisting step is carried out with a base yarn that is already twisted and a second base yarn which is in the form of a fiber roving.
A uniform twisted yarn with respect to both base yarns is produced with this method when the base yarn that is pretwisted has its twist canceled by twisting it counter to the spinning direction and when it is then twisted together with the roving coming from the drawing device in the hollow spindle axle. The yarn portion resulting from the roving is not provided with a twist in this method step. When both yarn portions are to have a same twist, as is expected from a balanced twisted yarn, then this can only be achieved when the twist of the spun yarn of the spun base yarn body resulting from the spinning process is canceled during the second method phase, i.e., during the twisting phase, so as to be completely canceled. With this method it is thus impossible to produce twisted yarns having an incompletely compensated twist.
It is therefore an object of the invention to provide a combined spinning and twisting method and a corresponding device with which it is possible to achieve in the finished twisted yarn any desired twist relation between the individual yarns, respectively, individual base threads, on the one hand, and the twisted yarn twist, on the other hand.
Twisted yarns of this character, i.e., with incompletely compensated twist, are most frequently employed.